Re: postgres on a beowulf? (AMD)opteron?

On Tue, 20 May 2003, Shridhar Daithankar wrote:

> On Monday 19 May 2003 22:58, george young wrote:
> > Has anyone run postgres on a beowulf system?
> >
> > I'm shopping for a new server. One candidate would be a
> > quad opteron (64-bit AMD "hammer") machine. Another approach might
> > be a beowulf of single or dual opterons. I imagine the beowulf
> > would be a bit cheaper, and much more expandable, but what about
> > the shared memory used by the postgres backends? I gather that
> > postgres uses shared memory to coordinate (locks?) between backends?
>
> Postgresql will not run on beowulf at all since it is an MPI system and
> postgresql can no span a single database across machines (yet). Further it
> won't even run on mosix because mosix does not support shared memory across
> machines.
>
> >
> > I have a smallish DB (pgdump|bzip2 -> 10MB), with ~45 users logged in
> > using local X(python/gtk) postgres client apps.
>
> Well, you haven't put how many transactions you do, but in general for that
> sort of DB, a P-IV/512MB RAM and SCSI disk would be more than enough unless
> you are doing really exotic things with data..
>
> > [Next question is: has anyone used postgres on an opteron at all??]
>
> Well, if it runs linux as good as anything else, postgresql will run as good
> as anything else..:-)

Keep in mind, if what you're doing is very memory intensive, then the PIV
with it's faster memory bandwidth may be the best bet. If it's CPU
processing intensive (GIS calculations) or I/O intensive the AMD's should
be competitive, but for memory I/O speed bound apps, the P IV is still
faster.

You'll not know which is faster until you've benchmarked it yourself under
your own load though. :-)